Results of a questionnaire regarding practice patterns for the diagnosis and treatment of intracranial radiation necrosis after SRS

Lung cancer with brain metastases remaining in continuous complete remission due to pembrolizumab and temozolomide: a case report

Background

Immunotherapy has been shown to improve the overall survival (OS) in patients with advanced or metastatic non-small cell lung cancer (NSCLC) without driver gene mutations. However, monotherapy with immunotherapy alone or combined with chemotherapy in NSCLC patients with untreated brain metastases (BM) is still under debate. Data regarding treatment of BM with immunotherapy and temozolomide (TMZ) in patients with NSCLC is rare.

Case Presentation

A 60-year-old male due to cough and expectoration presented in our hospital. Chest computed tomography (CT), brain magnetic resonance imaging (MRI) and immunohistochemistry of a mediastinal lymph node biopsy were administered, he was diagnosed with stage IIIB lung adenocarcinoma. Without driver gene mutations, he was treated with platinum-based chemotherapy because he refused to accept concurrent radiation therapy (RT). Heavy cough companied with hemoptysis and chest CT scan both revealed progressive disease (PD) after 6 cycles of chemotherapy. Immunotherapy was consequently considered, while two metastatic lesions in the brain were confirmed after combined treatment of pembrolizumab with docetaxel. TMZ was administered in combination with pembrolizumab (200 mg, day 1). A new metastasis in the right occipital lobe was detected on a scan 1 month later, though the other 2 lesions continued to shrink. The treatment was continued, MRI and CT scans suggested complete response (CR) was achieved for both the BM and lung lesions after 3 cycles. Consolidation therapy with TMZ and pembrolizumab (100 mg) per month was considered for another 7 months. Maintenance monotherapy with pembrolizumab (100 mg) was selected because of his stable CR status. At 59 months since diagnosis, the patient remains alive, with CR for both the primary lesions and BM. The patient experienced slight numbness on each side of his feet. There was no occurrence of adverse effects greater than grade 3.

Conclusions

The data indicates that immunotherapy combined with TMZ for untreated BM in NSCLC patients maybe an efficient and safe decision making therapeutic choice. Despite the encouraging efficacy of the combination, it is an isolated case and the speculation of synergism need to be proved in further pharmacokinetic/pharmacodynamic studies even in large randomized controlled trials.

Current emerging MRI tools for radionecrosis and pseudoprogression diagnosis

PURPOSE OF REVIEW

This review aims to cover current MRI techniques for assessing treatment response in brain tumors, with a focus on radio-induced lesions.

RECENT FINDINGS

Pseudoprogression and radionecrosis are common radiological entities after brain tumor irradiation and are difficult to distinguish from real progression, with major consequences on daily patient care. To date, shortcomings of conventional MRI have been largely recognized but morphological sequences are still used in official response assessment criteria. Several complementary advanced techniques have been proposed but none of them have been validated, hampering their clinical use. Among advanced MRI, brain perfusion measures increase diagnostic accuracy, especially when added with spectroscopy and susceptibility-weighted imaging. However, lack of reproducibility, because of several hard-to-control variables, is still a major limitation for their standardization in routine protocols. Amide Proton Transfer is an emerging molecular imaging technique that promises to offer new metrics by indirectly quantifying intracellular mobile proteins and peptide concentration. Preliminary studies suggest that this noncontrast sequence may add key biomarkers in tumor evaluation, especially in posttherapeutic settings.

SUMMARY

Benefits and pitfalls of conventional and advanced imaging on posttreatment assessment are discussed and the potential added value of APT in this clinicoradiological evolving scenario is introduced.

Toxicity and time lapse between immunotherapy and stereotactic radiotherapy of brain metastases

PURPOSE

Stereotactic radiotherapy (SRT) is the standard treatment for brain metastases of non-small-cell lung cancer (NSCLC) and melanoma, mostly in combination with immunotherapy. The objective was to retrospectively evaluate the influence of the time-lapse between immunotherapy and stereotactic radiotherapy on toxicity.

PATIENTS AND METHODS

From 2016 to 2019, 59 patients treated with SRT for 103 brain metastases of NSCLC (60%) and melanoma (40%) in combination with concomitant immunotherapy (≤30 days) were included. The prescribed dose was 20Gy/1f or 33Gy/3f at the isocentre and 14Gy or 23.1Gy (70%) respectively at the PTV envelope (PTV=GTV+2mm). The mean tumour diameter was 14mm (4-52mm). The immunotherapies used were anti-PD1 and anti-PDL1. The 103 metastases were classified into 3 groups according to the time-lapse between instatement of immunotherapy and instatement of SRT for the patient concerned: 7 (7%) in group A (≤7 days), 38 (37%) in group B (7 to 14 days) and 58 (56%) in group C (14 to 30 days).

RESULTS

The mean follow-up was 10.1 months. The median overall survival was 11.5 months for NSCLC and 12.5 months for melanoma. The percentage of local control (LC) at one year was 65.1% (93.6% for NSCLC and 26.5% for melanoma). The time-lapse between immunotherapy and SRT was not a significant predictor of LC (P=0.86), while the histology was (P<0.001). The proportion of grade≥3 toxicities was 5.1%, and that of radionecrosis was 9.7% (among these patients, 80% were non-symptomatic): 0%, 13.1% and 8.6% for groups A, B and C respectively. The time-lapse between immunotherapy and SRT was not a significant predictor of toxicity. Only tumour volume was a significant predictive factor (P=0.03).

CONCLUSION

The time lapse between immunotherapy and SRT does not influence brain toxicity. The tumour volume remains the main factor.

Hypofractionated stereotactic radiotherapy for large brain metastases: Optimizing the dosimetric parameters

PURPOSE

Stereotactic radiotherapy plays a major role in the treatment of brain metastases (BM). We aimed to compare the dosimetric results of four plans for hypofractionated stereotactic radiotherapy (HFSRT) for large brain metastases.

MATERIAL AND METHODS

Ten patients treated with upfront NovalisTx® non-coplanar multiple dynamic conformal arcs (DCA) HFSRT for≥25mm diameter single BM were included. Three other volumetric modulated arc therapy (VMAT) treatment plans were evaluated: with coplanar arcs (Eclipse®, Varian, VMATc_Eclipse®), with coplanar and non-coplanar arcs (VMATnc_Eclipse®), and with non-coplanar arcs (Elements Cranial SRS®, Brainlab, VMATnc_Elements®). The marginal dose prescribed for the PTV was 23.1Gy (isodose 70%) in three fractions. The mean GTV was 27mm³.

RESULTS

Better conformity indices were found with all VMAT techniques compared to DCA (1.05 vs 1.28, P<0.05). Better gradient indices were found with VMATnc_Elements® and DCA (2.43 vs 3.02, P<0.001). High-dose delivery in healthy brain was lower with all VMAT techniques compared to DCA (5.6 to 6.3 cc vs 9.4 cc, P<0.001). Low-dose delivery (V5Gy) was lower with VMATnc_Eclipse® or VMATnc_Elements® than with DCA (81 or 94 cc vs 110 cc, P=0.02).

CONCLUSIONS

NovalisTx® VMAT HFSRT for≥25mm diameter brain metastases provides the best dosimetric compromise in terms of target coverage, sparing of healthy brain tissue and low-dose delivery compared to DCA.

Single- and Multifraction Stereotactic Radiosurgery Dose/Volume Tolerances of the Brain

PURPOSE

As part of the American Association of Physicists in Medicine Working Group on Stereotactic Body Radiotherapy investigating normal tissue complication probability (NTCP) after hypofractionated radiation therapy, data from published reports (PubMed indexed 1995-2018) were pooled to identify dosimetric and clinical predictors of radiation-induced brain toxicity after single-fraction stereotactic radiosurgery (SRS) or fractionated stereotactic radiosurgery (fSRS).

METHODS AND MATERIALS

Eligible studies provided NTCPs for the endpoints of radionecrosis, edema, or symptoms after cranial SRS/fSRS and quantitative dose-volume metrics. Studies of patients with only glioma, meningioma, vestibular schwannoma, or brainstem targets were excluded. The data summary and analyses focused on arteriovenous malformations (AVM) and brain metastases.

RESULTS

Data from 51 reports are summarized. There was wide variability in reported rates of radionecrosis. Available data for SRS/fSRS for brain metastases were more amenable to NTCP modeling than AVM data. In the setting of brain metastases, SRS/fSRS-associated radionecrosis can be difficult to differentiate from tumor progression. For single-fraction SRS to brain metastases, tissue volumes (including target volumes) receiving 12 Gy (V12) of 5 cm³, 10 cm³, or >15 cm³ were associated with risks of symptomatic radionecrosis of approximately 10%, 15%, and 20%, respectively. SRS for AVM was associated with modestly lower rates of symptomatic radionecrosis for equivalent V12. For brain metastases, brain plus target volume V20 (3-fractions) or V24 (5-fractions) <20 cm³ was associated with <10% risk of any necrosis or edema, and <4% risk of radionecrosis requiring resection.

CONCLUSIONS

The risk of radionecrosis after SRS and fSRS can be modeled as a function of dose and volume treated. The use of fSRS appears to reduce risks of radionecrosis for larger treatment volumes relative to SRS. More standardized dosimetric and toxicity reporting is needed to facilitate future pooled analyses that can refine predictive models of brain toxicity risks.

Radiomics Method for the Differential Diagnosis of Radionecrosis Versus Progression after Fractionated Stereotactic Body Radiotherapy for Brain Oligometastasis

Stereotactic radiotherapy (SRT) is recommended for treatment of brain oligometastasis (BoM) in patients with controlled primary disease. Where contrast enhancement enlargement occurs during follow-up, distinguishing between radionecrosis and progression presents a critical challenge. Without pathological confirmation, decision-making may be inappropriate and delayed. Quantitative imaging features extracted from routinely performed examinations are of interest in potentially addressing this problem. We explored the added value of the radiomics method for the differential diagnosis of these two entities. Twenty patients who received SRT for BoM, from any primary location, were included (8 radionecrosis, 12 progressions, pathologically confirmed). We assessed the clinical relevance of 1,766 radiomics features, extracted using IBEX software, from the first T1-weighted postcontrast magnetic resonance imaging (MRI) after SRT showing a lesion modification. We evaluated seven feature-selection methods and 12 classification methods in terms of respective predictive performance. The classification accuracy was measured using Cohen's kappa after leave-one-out cross-validation. In this work, the best predictive power reached was a Cohen's kappa of 0.68 (overall accuracy of 85%), expressing a strong agreement between the algorithm prediction and the histological gold standard. Prediction accuracy was 75% for radionecrosis, and 91% for progression. The area under a curve reached 0.83 using a bagging algorithm trained with the chi-square score features set. These findings indicated that the radiomics method is able to discriminate radionecrosis from progression in an accurate, early and noninvasive way. This promising study is a proof of concept, preceding a larger prospective study for defining a robust model to support decision-making in BoM. In summary, distinguishing between radionecrosis and progression is challenging without pathology. We built a classification model based on imaging data and machine learning. Using this model, we were able predict progression and radionecrosis in, respectively, 91% and 75% of cases.

Ultra-Low-Dose Bevacizumab For Cerebral Radiation Necrosis: A Prospective Phase II Clinical Study

OBJECTIVE

To investigate the treatment efficacy of ultra-low-dose bevacizumab for cerebral radiation necrosis.

METHODS

Patients with cerebral radiation necrosis after stereotactic radiotherapy (SRT) confirmed by imaging were included. Bevacizumab (1 mg/kg, once every three weeks, for at least three continuous treatments) was administered. The primary endpoints included change in cerebral necrosis symptoms, volume of intracranial edema, and changes in MRI signals. The secondary endpoints were adverse reactions of bevacizumab treatment.

RESULTS

In total, 21 patients were included in this study, all of whom received SRT between December 2016 and February 2019, developed cerebral radiation necrosis, and were treated with bevacizumab. Twenty patients were symptomatic from radiation necrosis, and the symptoms were alleviated in 18 patients (90%). Twenty patients had intracranial edema, and the grade of edema index (EI) was improved in 19 patients (95%). The intensity of the intracranial-enhanced MRI signals was significantly reduced in 20 patients (95.24%). The adverse reactions of bevacizumab treatment were mild, and no adverse reactions more severe than grade 2 were found.

CONCLUSION

The preliminary results showed that ultra-low-dose bevacizumab had high efficacy for treating cerebral radiation necrosis, and could be a valid alternative to the standard-dose bevacizumab.

CLINICAL REGISTRY

Chinese clinical trial registry (ChiCTR-IOD-16009803).

Exploration of the recurrence in radiation brain necrosis after bevacizumab discontinuation

Objective: The aim of the paper was to investigate the recurrence and its causes of radiation brain necrosis following bevacizumab discontinuation. Methods: This study included 14 patients with radiation brain necrosis (confirmed through imaging) after stereotactic radiotherapy for a primary or metastatic brain tumor and who received bevacizumab treatment from June 2011 through December 2014. The patients received bevacizumab at 5 mg/kg, q3-4w, for at least 3 cycles. The T1 signal intensity from enhanced MRI images was used as the evaluation criteria for the brain necrosis treatment efficacy. Results: brain necrosis improved in 13 of the 14 cases (92.9%). However, during follow-up, 10 of the 13 responsive patients (76.9%) exhibited a recurrence in brain necrosis, and a multiple linear regression analysis shows that brain necrosis recurrence was related to the follow-up time after the initial bevacizumab treatment discontinuation. Conclusion: bevacizumab produced good short-term effects for radiation brain necrosis; however, most of the patients would recurrence after bevacizumab is discontinued. Thus, brain necrosis was irreversible.

Angiotensin receptor blockade: a novel approach for symptomatic radiation necrosis after stereotactic radiosurgery

Preclinical evidence suggests angiotensin blockade therapy (ABT) decreases late radiation toxicities. This study aims to investigate the association between ABT and symptomatic radiation necrosis (SRN) following stereotactic radiosurgery (SRS). Resected brain metastases (rBM) and arteriovenous malformation (AVM) patients treated with SRS from 2002 to 2015 were identified. Patients in the ABT cohort were on therapy during SRS and at 1-month follow up. Kaplan Meier method and cumulative incidence model were used to analyze overall survival (OS) and intracranial outcomes. 228 consecutive patients were treated with SRS: 111 with rBM and 117 with AVM. Overall, 51 (22.4%) patients were in the ABT group: 32 (28.8%) in the rBM and 19 (16.2%) in AVM cohorts. Baseline characteristics were similar, except for higher Graded Prognostic Analysis (3-4) in the rBM (ABT: 25.0% vs. non-ABT: 49.0%, p = 0.033) and median age in the AVM (ABT: 51.4 vs. non-ABT: 35.4, p < 0.001) cohorts. In both populations, OS and intracranial efficacy (rBM-local control; AVM-obliteration rates) were statistically similar between the cohorts. ABT was associated with lower 1-year SRN rates in both populations: rBM, 3.1 versus 25.3% (p = 0.003); AVM, 6.7 vs. 14.6% (p = 0.063). On multivariate analysis, ABT was a significant predictive factor for rBM (HR: 0.17; 95% CI 0.03-0.88, p = 0.035), but did not reach statistical significance for AVM (HR: 0.36; 95% CI 0.09-1.52, p = 0.165). ABT use appears to be associated with a reduced risk of SRN following SRS, without detriment to OS or intracranial efficacy. A prospective trial to validate these findings is warranted.

[Hypofractionated stereotactic radiotherapy for brain metastasis: Benefit of additional whole brain radiotherapy?]

PURPOSE

To study overall survival, risk of neurological death, local recurrence and development of new brain metastasis in patients treated for brain oligometastases with hypofractionated stereotactic radiotherapy with CyberKnife^®, according to the association or not with an additional whole brain irradiation.

PATIENTS AND METHODS

Institutional retrospective study of 102 patients treated for one to three brain metastasis: 76 with exclusive hypofractionated stereotactic radiotherapy and 26 with hypofractionated stereotactic radiotherapy and whole brain irradiation. Objectives were assessed and compared between these two groups according to the Kaplan-Meier method and Cox model.

RESULTS

Median follow-up was 18.8 months. There were no difference between exclusive hypofractionated stereotactic radiotherapy and hypofractionated stereotactic radiotherapy with whole brain irradiation for overall survival (respective median 21.5 and 20.1 months), risk of neurological death (respectively 9.2% and 15.4% at one year). At one year: the risk of cerebral progressive disease was greater in the group receiving exclusive hypofractionated stereotactic radiotherapy (respectively 43.4% vs. 26.2%, P=0.043), the risk of local recurrence was 25% versus 17.6% (P=0.28) and the development of new brain metastasis was 23.7% versus 11.5% (P=0.27). After salvage treatments, crude local control was similar in the two groups, respectively 78.6% and 73.5%. Whole brain irradiation has been avoided for 72.4% of patients in the group receving exclusive hypofractionated stereotactic radiotherapy.

CONCLUSION

Whole brain irradiation improves local control of brain metastatic disease in addition to hypofractionated stereotactic radiotherapy. Sparing whole brain irradiation for salvage treatments only does not affect overall survival or risk of neurological death in selected patients with favourable prognosis.

Analysis of risk and predictors of brain radiation necrosis after radiosurgery

In this study, we examined the factors contributing to brain radiation necrosis and its predictors of patients treated with Cyberknife radiosurgery. A total of 94 patients with primary or metastatic brain tumours having been treated with Cyberknife radiotherapy from Sep. 2006 to Oct. 2011 were collected and retrospectively analyzed. Skull based tracking was used to deliver radiation to 104 target sites. and the prescribed radiation doses ranged from 1200 to 4500 cGy in 1 to 8 fractions with a 60% to 87% isodose line. Radiation necrosis was confirmed by imaging or pathological examination. Associations between cerebral radiation necrosis and factors including diabetes, cardio-cerebrovascular disease, target volume, isodose line, prescribed dosage, number of fractions, combination with whole brain radiation and biologically equivalent dose (BED) were determined by logistic regression. ROC curves were created to measure the predictive accuracy of influence factors and identify the threshold for brain radiation necrosis. Our results showed that radiation necrosis occurred in 12 targets (11.54%). Brain radiation necrosis was associated by BED, combination with whole brain radiotherapy, and fractions (areas under the ROC curves = 0.892±0.0335, 0.650±0.0717, and 0.712±0.0637 respectively). Among these factors, only BED had the capability to predict brain radiation necrosis, and the threshold dose was 7410 cGy. In conclusion, BED is the most effective predictor of brain radiation necrosis, with a dose of 7410 cGy being identified as the threshold.

A study on the evaluation method and recent clinical efficacy of bevacizumab on the treatment of radiation cerebral necrosis

In order to investigate the efficacy of bevacizumab on the treatment of radiation cerebral necrosis, patients who were diagnosed with radiation cerebral necrosis by imaging after stereotactic radiotherapy were collected. Bevacizumab was applied at a dose of 5 mg/kg once every three weeks at least three times. The changes in cerebral necrosis symptoms before and after treatment, the cerebral edema volume, the cerebral necrosis volume, and the changes in magnetic resonance imaging (MRI) strengthening phase signals of cerebral necrosis were used as the first observation point. The side effects of bevacizumab were used as the second observation point. Total of 14 radiation cerebral necrosis patients were treated with bevacizumab between June 2011 and February 2013 were collected. There were 12 symptomatic patients, of whom 10 patients (83.3%) had reduced symptoms. The edema index grades of nine patients (64.29%) improved. The cerebral necrosis volumes of 13 patients (92.86%) decreased. The T1 phase signal strengths of the intracranial enhanced MRIs of 12 patients (85.71%) significantly decreased. The clinical side effects of bevacizumab were mild. In conclusion, Preliminary results showed that treatment of radiation cerebral necrosis using bevacizumab was safe and effective. This treatment measure is worthy of further study.

Impact of provider level, training and gender on the utilization of palliative care and hospice in neuro-oncology: a North-American survey

Specialized palliative care (PC) services have emerged to address symptoms and provide end-of-life management for patients with brain tumors. The utilization patterns of PC in neuro-oncology are unknown. A 22-question survey was distributed to participants of the society for neuro-oncology annual meeting 2012 (n = 4487). Nonparametric methods including Wilcoxon two-sample and Kruskal-Wallis tests were used to assess differences in responses. 239 (5.3 %) evaluable responses were received; 79 % of respondents were physicians, and 17 % were nurses or midlevel providers. Forty-seven percent were medical or neuro-oncologists, 31 % neurosurgeons and 11 % radiation oncologists. Forty percent had no formal training in PC, 57 % had some formal training and 3 % completed a PC fellowship. Seventy-nine percent practiced in an academic setting. Of the respondents, 57 % referred patients to PC when symptoms required treatment and 18 % at end of life. Only 51 % of all providers felt comfortable dealing with end-of-life issues and symptoms, while 33 % did not. Fifty-one percent preferred a service named "Supportive Care" rather than "Palliative Care" (MDs > midlevel providers, p < 0.001), and 32 % felt that patient expectations for ongoing therapy hindered their ability to make PC referrals. Female gender, formal training in neuro-oncology and PC, and medical versus surgical neuro-oncology training were significantly associated with hospice referral, comfort in dealing with end-of-life issues, and ease of access to PC services. Provider level, specialty, gender, training in PC and neuro-oncology have significant impact on the utilization of PC and hospice in neuro-oncology.

International patterns of palliative care in neuro-oncology: a survey of physician members of the Asian Society for Neuro-Oncology, the European Association of Neuro-Oncology, and the Society for Neuro-Oncology

Background

Brain tumor patients have limited survival and suffer from high morbidity requiring specific symptom management. Specialized palliative care (PC) services have been developed to address these symptoms and provide end-of-life treatment. Global utilization patterns of PC in neuro-oncology are unknown.

Methods

In a collaborative effort between the Society for Neuro-Oncology (SNO), the European Association of Neuro-Oncology (EANO), and the Asian Society for Neuro-Oncology (ASNO), a 22-question survey was distributed. Wilcoxon 2-sample and Kruskal-Wallis tests were used to assess differences in responses.

Results

Five hundred fifty-two evaluable responses were received. The most significant differences were found between Asia-Oceania (AO) and Europe as well as AO and United States/Canada (USA-C). USA-C providers had more subspecialty training in neuro-oncology, but most providers had received no or minimal training in palliative care independent of region. Providers in all 3 regions reported referring patients at the onset of symptoms requiring palliation, but USA-C and European responders refer a larger total proportion of patients to PC (P < .001). Physicians in AO and Europe (both 46%) as well as 29% of USA-C providers did not feel comfortable dealing with end-of-life issues. Most USA-C patients (63%) are referred to hospice compared with only 8% and 19% in AO and Europe (P < .001), respectively.

Conclusion

This is the first report describing global differences of PC utilization in neuro-oncology. Significant differences in provider training, culture, access, and utilization were mainly found between AO and USA-C or AO and Europe. PC patterns are more similar in Europe and USA-C.

Cerebral peduncle tumor ablated by novel 3-mm laser tip

BACKGROUND/OBJECTIVE

Decisions to use open surgery or radiotherapy in pediatric patients with familial neoplastic syndromes must consider not only the symptomatic benefits of treatment, but also future limitations these treatments may impose. Specifically, open surgical resection of noncurable tumors may preclude or encumber future lesion resections, while radiotherapy has detrimental effects on pediatric cognitive development and increases the risk of future malignancy development. We provide the first report of using a novel 3.0-mm diffusing laser tip with laser-induced thermal therapy (LiTT) to treat a pediatric patient with neurofibromatosis type 1 (NF-1).

METHODS

A 12-year-old boy with NF-1 presented with a progressively enlarging lesion in the right midbrain. A stereotactic biopsy was performed, followed by LiTT with a novel 3.0-mm laser applicator.

RESULTS

MRI 1 week after LiTT showed stable gross total ablation of the lesion with reduction in fluid-attenuated inversion recovery signal. The patient remained neurologically intact 6 months after his procedure, and follow-up MRI showed no evidence of recurrence.

CONCLUSION

LiTT is a powerful adjunct to conventional open surgical and radiotherapy modalities in the treatment of patients with familial neoplastic syndromes or incurable lesions. The novel laser applicator tip described expands the treatment scope of this technique.

Changes in protein level in the cerebrospinal fluid of a patient with cerebral radiation necrosis treated with bevacizumab

A 32-year-old woman underwent surgeries and radiation therapy for astrocytoma. She developed symptomatic radiation necrosis in the lesion, which caused hydrocephalus. She initially underwent ventricular drainage, because the protein level in the cerebrospinal fluid (CSF) was 787 mg/dL, which was too high for shunt surgery. Because she also had breast cancer, which was pathologically diagnosed as an invasive ductal carcinoma, standard bevacizumab therapy in combination with paclitaxel every 2 weeks was selected. Interestingly, after 2 days, the agents had dramatically reduced the CSF protein level. However, it returned to approximately the initial level within 2 weeks. After two courses of this regimen, a ventriculoperitoneal shunt was placed. After 10 courses of this regimen, the CSF protein level decreased to 338 mg/dL, which is less than half of the initial level. Long-term administration of bevacizumab might decrease leakage of protein from the vessels around the ventriculus.